for the people who cant get it in devices. the problem is that "bonjour" isn't on. bonjour allows itunes to share its music. for windows. start>run>services.msc>Bonjour Services>Rightclick-properties> automatic and click start.

In iTunes click edit - preferences, then click on the shared tab and check the box for share my library on my local network. Then restart itunes, open remote.app on ur touch/iphone and it should show up on the left in itunes. Hope this helps

Take a look in System Preferences -> Sharing. Make sure your computer has a name and .local address, and try turning File Sharing on. Also, try (temporarily) turning your Firewall off (Firewall settings are in the Sharing prefpane if your using Tiger or earlier; Security prefpane if your using Leopard.)

Are you sure that your iPod/iPhone and Mac are connected to the same LAN and both have been assigned IP addresses?